Upgrading Managed Servers

Jul 01, 2013

You can use the
Rolling
Pool Upgrade wizard to upgrade XenServer hosts - hosts in a pool or
standalone hosts - from XenServer version 5.6 or later to a newer version. For
information about how to upgrade from earlier versions of XenServer, see the
XenServer
Installation Guide.

The wizard guides
you through the upgrade procedure and organizes the upgrade path automatically.
For pools, each of the hosts in the pool is upgraded in turn, starting with the
pool master. Before starting an upgrade, the wizard conducts a series of
prechecks to ensure that certain pool-wide features, such as HA and WLB, are
temporarily disabled and that each host in the pool is prepared for upgrade
(for example, that the CD/DVD drive of each host is empty). Only one host is
offline at a time, and any running VMs are automatically migrated off each host
before the upgrade is installed on that host.

The wizard can
operate in
manual
or
automatic mode:

In manual mode,
you must manually run the XenServer installer on each XenServer host in turn
and follow the on-screen instructions on the serial console of the host. Once
the upgrade begins, XenCenter prompts you to insert the XenServer installation
media or specify a PXE boot server for each host that you upgrade.

In automatic
mode, the wizard uses network installation files located on an HTTP, NFS or FTP
server to upgrade each host in turn, without requiring you to insert install
media, manually reboot, or step through the installer on each host.

You can also use
the
Rolling
Pool Upgrade wizard to upgrade standalone hosts, that is, hosts
which are not in a pool.

Important:
Before you upgrade

Upgrading a pool
of XenServer hosts requires careful planning. As you plan your upgrade, it is
very important to be aware of the following:

VMs can only
be migrated from a XenServer host running an older version of XenServer to one
running the same version or higher (for example, from version 5.5 to version
5.5 or from version 5.5 to version 5.6). You cannot migrate VMs from an
upgraded host to one running an older version of XenServer (for example, from
version 5.6 to version 5.5). Be sure to allow for space on your XenServer hosts
accordingly.

Citrix
strongly advises against running a mixed-mode pool (one with multiple versions
of XenServer coexisting) for longer than necessary, as the pool operates in a
degraded state during upgrade.

Key control
operations are not available during upgrade and should not be attempted. Though
VMs continue to function as normal, VM actions other than migrate may not be
available (for example, shut down, copy and export). In particular, it is not
safe to perform storage-related operations such as adding, removing or resizing
virtual disks.

The wizard
will always upgrade the master host first. Do not place the master into
maintenance mode using XenCenter before performing the upgrade as this will
cause a new master to be designated.

Take a backup
of the state of your existing pool using the
pool-dumpdatabase xe CLI command (see the
XenServer
Administrator's Guide). This allows you to revert a partially complete
rolling upgrade back to its original state without losing any VM data. Because
it is not possible to migrate a VM from an upgraded XenServer host to a
XenServer host running an older version of XenServer, it may be necessary to
shut down VMs if you need to revert the rolling upgrade for any reason.

Ensure that
your hosts are not over-provisioned - that they have sufficient memory to carry
out the upgrade. It is best to suspend any VMs that are not critical during the
upgrade process.

While the
Rolling Pool Upgrade wizard checks that the
following actions have been taken, you may choose to perform them before you
begin the upgrade:

Empty the
CD/DVD drives of the VMs in the pool(s). For details and instructions, see the
XenServer Installation Guide.

To upgrade
XenServer hosts using the Rolling Pool Upgrade wizard

Read the
Before You Start information, and then click
Next to continue.

Select the
pool(s) and/or individual hosts that you wish to upgrade and then click
Next.

Choose
Automatic Mode or
Manual Mode, depending on whether you are planning
an automated upgrade from network installation files located on an HTTP, NFS or
FTP server, or a manual upgrade from either a CD/DVD or a server via PXE boot.

Note: If you
choose
Manual Mode, you must run the XenServer installer on
each XenServer host in turn and follow the on-screen instructions on the serial
console of the host. Once the upgrade begins, XenCenter prompts you to insert
the XenServer installation media or specify a PXE boot server for each host
that you upgrade.

Once you
have selected your Upgrade Mode, click
Run Prechecks.

Follow the
recommendations to resolve any upgrade prechecks that have failed. If you would
like XenCenter to automatically resolve all failed prechecks, click
Resolve All.
Once
all prechecks have been resolved, click
Next to continue.

Prepare the
XenServer installation media:

If you
chose
Automatic Mode, enter the installation media
details. Choose
HTTP,
NFS or
FTP and then specify the path, username and
password, as appropriate.

If you
chose
Manual Mode, note the upgrade plan and instructions.

Click
Start Upgrade to begin the upgrade.

Once the
upgrade begins, the wizard guides you through any actions you need to take to
upgrade each host. Follow the instructions until you have upgraded all hosts in
the pool(s).

Once the
upgrade completes, the wizard prints a summary. Click
Finish to close the wizard.

After
upgrading

Support for
RBAC was introduced at XenServer version 5.6. Any user accounts created in
earlier XenServer releases are assigned the role of Pool Admin when upgrading
to XenServer version 5.6 or later. This is done for backwards compatibility
reasons. When upgrading from older XenServer releases, you should revisit the
role associated with each user account to make sure it is still appropriate.